Dr. Blackmore's overall career goal is to examine and improve the role of radiology in optimizing efficiency in patient care at the patient and system levels. In particular, he will develop and apply clinical prediction rules and other decision-making tools to aid cost-effective use of emergency radiology services. This Research Career Award has three broad objectives that will enable Dr. Blackmore's progression to independent researcher. First, it will expand his research skills through a program of formal coursework and informal mentoring focused on: 1) advanced techniques in data analysis, particularly survival analysis, and epidemiological methods for clinical prediction rules; 2) multi- institutional research design, implementation and analysis; and 3) injury epidemiology and research. Second, the investigator will gain practical experience through the development and validation of the pelvic hemorrhage prediction rule detailed below, and third, Dr. Blackmore will establish a network of regional trauma centers that will facilitate future investigations. The research portion of this Research Career Award proposes to develop and validate a simple instrument to determine which subjects with pelvic fracture have a high probability of major hemorrhage. Fracture of the pelvis can lead to life-threatening hemorrhage that may not be clinically apparent in the immediate setting. Delay in diagnosis leads to morbidity, and contributes to the 1000 pelvic fracture related deaths that occur each year in the US. The intent of this four-phase project is to develop a simple prediction rule based on radiographic findings and clinical factors that can be applied immediately to rapidly identify patients at risk for such major hemorrhage. The specific aim of Phase 1 is the determination of the relationship between measured pelvic hemorrhage volume and outcome, through CT scan based measurement of pelvic hemorrhage, and retrospective chart review of outcome on a cohort of 400 patients with pelvic fracture. The volume of hemorrhage associated with adverse outcome will be determined. Phase 2 has as a specific aim the development of the prediction rule through the evaluation of medical records and pelvic radiographs on a cohort of 1000 pelvic fracture patients from 7 trauma centers in Western Washington. Radiographic and clinical factors that predict major hemorrhage will be identified through regression and survival analysis. Phase 3 is the assessment of the reliability of the radiographic predictors by evaluating the agreement of 12 readers on a set of 25 pelvic fracture radiographs. Finally, the specific aim of Phase 4 will be a multi-center prospective validation of the prediction rule involving 750 subjects at three trauma centers. The ability of the prediction rule to accurately identify subjects with major hemorrhage will be determined. The completed and validated prediction rule will provide an efficient method of using the pelvic radiograph in conjunction with simple clinical data to select appropriate subjects for triage to higher level trauma centers, and to guide immediate therapy.